Our database (10gR2) is running on AIX 6.1 and using ASM with a single disk group. The disk group is currently not mounted, and when trying alter diskgroup mount, the following error is returned: ORA-15024: discovered duplicately numbered ASM disk

A few new disks had been added and a rebalance completed. Then 10 new disks were added with a rebalance power of 0 (I guess in order to hold off the rebalance operation). The DBA then started to increase tablespaces, thinking the new disks were ready.

Disks in the diskgroup started to dismount as they ran out of space. The entire diskgroup finally came down causing the database to crash. There are currently 130 disks assigned to ASM, but when looking at v$asm_disks, the disk_number goes to 132, with two values missing. However, all of the physical disks are accounted for in the PATH column. It also seems that they have been shifted. For example, /dev/asm_disk030 has a disk_number of 33 now rather than 30 it had before.

Any help is appreciated. This seems like an error that should be able to be recovered from. Thanks!